How one undergrad built the largest solar farm in Michigan

University of Michigan undergraduate Connor Field designed and largely built …

Building a solar farm isn't hard if you have the money; you just pay contractors to show up, install electrical service, build the solar panel support infrastructure, and truck in the panels. But if you want to do it cheap, you could buy some land from a friend and set up your own fabrication shop, spending an entire summer welding together 50,000 pounds of structural steel and pouring concrete around 20,000 pounds of rebar to save serious cash on the infrastructure.

Connor Field, a Michigan resident who built the largest solar farm in the state this way in late 2009, said drily, "I would not do that again."

"Do you know how to weld?" I asked him when we met recently in Ann Arbor to discuss the project.

"I do now."

A solar farm, whose sole purpose is to soak up much sun energy as possible, loses out if its panels remain locked in a fixed position. The sky position of the sun varies throughout the year, and moving the panels periodically is essential to efficient systems. Unfortunately, when Field decided to build his own solar farm, he couldn't get a moveable "tracker" system for anything that was "close to reasonable"—so he built one himself. Even with the startup costs of equipping his own fabrication plant, the do-it-yourself approach was so much cheaper that it looked like a necessity if his project was to break even.

Field's trackers are simple steel structures with a hinged mechanism that allows the panel to be unlatched and then tilted into several specific angles based on time of year; the design is based on research from federal renewable energy studies. Field's two acre parcel of land—just off I-94 beyond a Target distribution center in rural Michigan—can have all its panels moved by 2 people in just 30 minutes. The setup was 8-10 percent more efficient than a fixed solar array, and when built was one of the most efficient large array systems in the state.

This wasn't a project installed by a major corporation; indeed, what's most remarkable about the solar farm is that Field is still a student studying both economics and electrical engineering at the University of Michigan. When we met, he had just come from a final exam.

Solar power isn't just for Arizona

Long interested in renewable energy, Field entered the university as an economics major and began researching energy projects in his spare time. “I went through a series of very bad ideas,” he said, before coming to the conclusion that “building wind generation infrastructure in Michigan is a terrible idea.”

But solar didn't look so bad. While it's true that sunny states like Arizona capture the public's imagination when it comes to solar, Midwestern states like Michigan can be workable. Arizona gets two-thirds more sun than Michigan's average of four usable hours of sun per day. But Arizona is also significantly warmer than Michigan, and most solar panels are significantly limited by heat. On Field's own solar farm, the effect is easy to see. His monitoring equipment shows that, on an 80 degree day, his panels drop to 75 percent of their maximum efficiency and decay from there as the temperature rises.

Thanks largely to this temperature affect, Field's farm produces more power in the spring than in the summer. The total solar array can produce a maximum of 149kW, enough to power a couple hundred homes, but it never exceeds 130kW in summer thanks to the temperature effect and to the higher summer humidity (which scatters the light).

Field had a simple goal with the farm—“not to lose money on the first project"—and added that he's “not interested in proving that solar's not economically viable." Losing money on renewable power is simple; it's turning a profit that's hard.

And Field wants to show that renewable tech, even on this scale, can be profitable. To do so, he partnered with his father (a lawyer) and with a family friend who owned 250 acres of land outside Battle Creek. To reduce risk on the project, the team negotiated a 12-year fixed rate for their power from the local electric company Consumer's Energy. (Making that deal was made easier by a state guideline that 10 percent of power come from renewable sources by 2015, and by a Consumer's Energy feed-in tariff program for arrays up to 150kW.) The panels have a rated life of 25 years (after which they should still produce electricity at 80 percent of their initial efficiency), so calculating a break-even date was straightforward.

The challenge came in upfront construction costs when it became clear that a moveable commercial tracker system was simply too expensive. Field's decision to build the entire set of support structures with his father shaved costs significantly, but the team still had to bring in an electrical contractor ($80,000), purchase the panels from Evergreen Solar, buy the electrical inverters that make the panel power compatible with the electrical grid, set up their small factory, and get structural engineers to look at overall site designs and at the concrete footings used to hold the arrays.

An interview with Sam Field, Connor's father

Field and his father coordinated all this work and were on-site watching most of it get done. The idea wasn't just to save money; it was to get a crash course in all the necessary disciplines associated with large-scale renewable power projects.

“The goal was to learn how to do it,” said Field, and the numerous mistakes the team made were dubbed "tuition moments."

In the end, it all worked as planned, and the solar farm now nearly runs itself. As we talked, Field pulled out his iPhone and showed me the farm's realtime power generation stats, which are pulled directly from the inverters and available over the Internet. Combined with perimeter security system and some live-feed Internet video cameras, Field can keep an eye on the team's investment from an Ann Arbor classroom without having to run back constantly to check that everything is functioning properly.

Problems cropped up, of course. Nearby lightning strikes blew out fuses at the farm, while the light beams on the security perimeter failed (twice) without any apparent reason.

But the most serious issue came from the taxman. After installation of the solar farm on its two acres of land, the local tax assessor upgraded the site from "leasehold improvement" to "real commercial property"—and property taxes went up dramatically. The team believes the designation is improper, and the legal expertise of Field's father has proven helpful as the decision is appealed.

The project was designed to break even in 12 years, but the higher tax rates could throw off that calculation. Field has learned his lesson from the tax scrap; his new projects now get "prenegotiated" tax rates from local townships to avoid these kinds of unexpected surprises, and he's found that most towns welcome well-thought-out, financially viable renewable power projects.

Now that the key lessons have been learned, Field is forging ahead with several more ventures, though he's hesitant to say too much about them yet. One hint: they will all be significantly larger than the solar farm, which required electrical service work that could serve a much larger project for the same amount of investment. Motorized panel tracking systems have dropped dramatically in price, and Field plans to buy in bulk for future projects, so hot summers of welding are behind him.

Indeed, Field is spending this summer interning with a University of Michigan project researching new solar technology. He's also developing future projects of his own, including one that should get under construction by summer's end. Not bad for an undergrad.

Despite the hard work involved, Field has some simple advice for anyone who might follow his lead: "Do it."

80 Reader Comments

The property tax issue seems underhanded. Not so much that the property designation was changed in order to collect more taxes, but that they knew this farm was being developed and said nothing until it was time to collect.

Although I must admit I see efforts like this (and a lot of other small businesses) as almost a social sacrifice. If he took all the time he and his dad put into this 'for free', and worked out the value of that time, it might make a significant difference to the profitability :-) These sorts of things really are a labor of love for some, and you never know, as he develops new projects that scale the size up and the relative costs down he may well end up very rich.

Only need another half million or so enthusiastic people like him to do something like this and you got all the households in the USA covered for electricity (in the day time) ;-)

This is really commendable. Now that he has a fabrication plant and construction expertise, the future projects might be even cheaper. If done right, we can have capitalist economy while still preserving our planet.

That is pretty impressive. It's great to see motivated, passionate individuals pursue stuff like this. Even better when they are young and still in college.

Out of curiosity, do you know what the total dollar amount of invested money went into the project? How much was out of the Fields' own pocket versus investors? What about total months to build? Total man-months of labor?

Out of curiosity, do you know what the total dollar amount of invested money went into the project? How much was out of the Fields' own pocket versus investors? What about total months to build? Total man-months of labor?

I too would like to know these things. The total amount must be at least, say, half a million dollars – presumably considerably more? I’m guessing.

Re investors, how were they found? Were they in the business of funding renewable energy projects? How were they persuaded this was worth funding? Was it difficult?

This is really commendable. Now that he has a fabrication plant and construction expertise, the future projects might be even cheaper. If done right, we can have capitalist economy while still preserving our planet.

I'd agree that it would be awesome, but the sad fact is that not everyone works for free, and I don't think this guy wants to set up the solar infrastructure of the country. Doing (almost) everything on his own with help from family, and he's still hoping to break even by the end of his contract.

Quoting my father on this one - "If you're not going into business to make money, then you're in the wrong profession." Taking losses isn't going to put bread on the table for anyone. Costs across the board have to drop significantly more before this becomes a viable solution for widespread adoption.

Is cooling these things really that big of an issue? How hard would it be to dig a few pipes underground as the sink for a simple liquid cooling loop? At most, you'd just need a small pump to keep whatever liquid it is flowing. Granted, you won't cool it to where it hits max efficiency like that, but even a 10% increase is huge, and probably more than enough to compensate for the pump's power requirements. Napkin calcs gives you a rough difference of 22deg C, assuming the panels hit something like 90deg surface temp on an 80deg day (probably a low estimate, but I'm not a solar guy). Probably something for a larger installation where the smaller numbers make a bigger deal, but just a thought.

And a long-term investment for the man and his father - break-even after twelve years on panels that will generate electricity for possibly three or four times that duration (albeit at lower efficiency as they get older) could mean a nice income in a few years.

As I've always thought - once you have some money, you can invest it in such projects and then get a steady income for years to come. In those terms investing your own time for free is perfectly reasonable if you can still afford to live day to day whilst doing that work.

Never knew until I read this article that efficiency of solar panels go down with higher temperatures. And I still don't believe it. Could you please tell us why that is so? Do you have a chart that shows temperature versus efficiency?

The property tax issue seems underhanded. Not so much that the property designation was changed in order to collect more taxes, but that they knew this farm was being developed and said nothing until it was time to collect.

What I thought as well

It's sad really when greed rears its ugly head like this: money over community and clean energy.

Depends on the mass and angle of impact. I imagine pea-sized hail is fine, golf ball-sized hail is iffy, baseball-sized hail is dangerous.

Samsung tests their panels with 25mm hail at 23 m/s (wonder if their panel specs meant 25g not 25mm).

UL1703 is the UL photovoltaics testing standard. At least some panel manufacturers (Sanyo, Samsung for at least some panel lines) test their panels accordingly. It specifies an impact test consisting of a 5 ft-lb (6.78J) impulse (delivered by a 2" diameter 1.18lb steel ball falling from a distance of 51 inches) normal to the panel surface. That's equivalent to a 25g (35mm or 1.5" diameter) piece of hail traveling at 23 m/s.

Fixed panels will be tilted at a latitude angle (for Huntsville, 34 degrees) relative to horizontal, to directly face the average position of the sun. Moveable panels like the ones mentioned in the article will have a shallower tilt in the summer and a steeper tilt in the winter. Supposing that hail comes straight down (not always the case), the angle tilt will mitigate some of the impact.

So are they going to write a book or something? It seems like they should... Plenty of folks are probably interested in the technical system design at a more in depth level than discussed here - and addressing all of the zoning and technical requirements would also be really interesting, I think.

Also, we need to hear about the tuition moments!

It seems like writing a book, even a digital only one, could also help to expedite the ROI timeline for the project and give value to the personal time and sweat equity invested....

The property tax issue seems underhanded. Not so much that the property designation was changed in order to collect more taxes, but that they knew this farm was being developed and said nothing until it was time to collect.

What I thought as well

It's sad really when greed rears its ugly head like this: money over community and clean energy.

This is really commendable. Now that he has a fabrication plant and construction expertise, the future projects might be even cheaper. If done right, we can have capitalist economy while still preserving our planet.

I'd agree that it would be awesome, but the sad fact is that not everyone works for free, and I don't think this guy wants to set up the solar infrastructure of the country. Doing (almost) everything on his own with help from family, and he's still hoping to break even by the end of his contract.

Quoting my father on this one - "If you're not going into business to make money, then you're in the wrong profession." Taking losses isn't going to put bread on the table for anyone. Costs across the board have to drop significantly more before this becomes a viable solution for widespread adoption.

Is cooling these things really that big of an issue? How hard would it be to dig a few pipes underground as the sink for a simple liquid cooling loop? At most, you'd just need a small pump to keep whatever liquid it is flowing. Granted, you won't cool it to where it hits max efficiency like that, but even a 10% increase is huge, and probably more than enough to compensate for the pump's power requirements. Napkin calcs gives you a rough difference of 22deg C, assuming the panels hit something like 90deg surface temp on an 80deg day (probably a low estimate, but I'm not a solar guy). Probably something for a larger installation where the smaller numbers make a bigger deal, but just a thought.

I did not know about solar panels losing efficiency at higher temps. So all those solar installations in California arn't working as well as they could in the summer.

Side note: Nice to see a young person investing time and energy in my state. Good job Connor!

Its actually pretty chilly in California, it usually stays below 80 during mid summer. In fact when that heat wave hit the US a week or two ago that pushed temperatures over 100 everywhere, it was 58 in San Francisco and 66 in LA.

Never knew until I read this article that efficiency of solar panels go down with higher temperatures. And I still don't believe it. Could you please tell us why that is so? Do you have a chart that shows temperature versus efficiency?

"Contrary to popular belief, the efficiency of a solar cell decreases with increasing temperature. The reason for this, is that a higher temperature increases the conductivity of the semiconductor. This balances out the charge within the material, reducing the magnitude of the electric field at the junction. This in turn inhibits charge separation, which lowers the voltage across the cell. It should be noted that a higher temperature increases the mobility of electrons, which causes the flow of current to increase slightly. This increase is however minor and insignificant compared to the decrease in voltage."

Like his father said in the video interview: these kind of projects should be taxed low, or even entirely exempt to encourage more people to follow with similar projects. We really need to get off oil and coal. I know many people don't believe that or don't care, but our costs of living are going up mainly due to expensive energy. We need more people like this and we need more projects like this so the costs of solar installations will drop. This is free energy people, and there is another billion or so years worth of supply of it.

It looks like Consumers' Energy pays small operations the market rate for power: they're remarkably transparent about how much they'll pay you and on what terms. That makes this PV plant all the more impressive: while we can't be sure what contract it has with the utility, it's likely that they're actually making a profit at something resembling a market rate for power.

My first thought, upon reading this, was that he must be getting some ridiculous subsidized rate for his power, like the 80MW Sarnia Photovoltaic Plant in Ontario - one of the largest PV installations in the world - that gets paid $0.443 / kWh. Depending on what you're comparing it to, that's five to ten times the cost of other power generation methods.

It's nice to see that solar power can be viable without huge subsidies.

More people with a lot of financial resources, to the extent that they can take a summer off, and build and outfit a machine shop, and get two acres of land apparently for free because of their connections, buy hundreds of thousands of dollars in supplies and contract labor out of pocket, and sink all of these resources into a project with no ROI.

Seems like the ideal place could be high mountains in the dessert where you would have low humidity and temperatures, Maybe even back the panels with large heat sinks that would cool at night. Of course not a lot of people to use the power there and the cost of running power lines would be high. No such thing as a free lunch.

I would like to know more of the actual numbers from the project as well. I wonder if the missed opportunity cost is calculated as well, such as "What kind of numbers could I be looking at if I invested the startup capital in an S&P 500 tracker with an annualized return of 9.5%." Would the estimated profit after the break-even point even come close?

I wonder what maintenance costs will look like after a few Michigan winters, as well.

Knowing how the US works, I'm just waiting to see these poor guys be sued for some form of patent/copyright infringement!

That said, I'm hoping his father is able to give the taxman the what-for. I agree that it seems rather underhanded to change the property tax classification. I'm surprised they didn't, also, increase the value of the property itself based on the value of the technology that was created (which could, probably, be considered a permanent structure much like a barn or the like).

That article about the taxes really lays bare how cheap the project is. We have a lot of comments about how you have to be filthy rich to attempt this, but if a $25k annual tax bill is the stumbling block and he expects ROI in 12 years, that puts an upper limit of $300k or so on the cost of the project. Not a trivial amount of money, but well within institutional reach.

It also means not a single Michigan utility saw fit to actually invest real money in renewable energy. How's that quest to become a leader in renewable energy working out for you?

I am really curious about the total cost of the project. It would be interesting to see rural and suburban neighborhoods use smaller solar farms like this to go off the grid. As the father says in video a lot of the equipment involved is extremely expensive because there is very little volume in sales.